Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($) Customer	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) Customer Segment	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) Customer
Summary Of Significant Accounting Policies [Line Items]
Number of major customers representing outstanding trade receivables | Customer	3		3		3
Life of inventory			2 years
Protracted length of inventory			1 year
Inventory valuation reserves	$ 700,000		$ 700,000		$ 1,800,000
Estimated useful life of intangible assets			10 years
Number of reportable segments | Segment			1
Impairment charges on long-lived assets	0	$ 0	$ 0	$ 0
Period of warranty			1 year
Warranty claim liability	0		$ 0		0
Other current assets	5,457,000		5,457,000		4,755,000
Other assets	2,207,000		2,207,000		2,579,000
Debt - current	4,969,000		4,969,000		2,956,000
Debt - non-current	$ 14,382,000		$ 14,382,000		16,848,000
Accounting Standards Update 2015-03 | Scenario, Previously Reported
Summary Of Significant Accounting Policies [Line Items]
Other current assets					32,000
Other assets					36,000
Accounting Standards Update 2015-03 | Scenario, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Other current assets					(32,000)
Other assets					(36,000)
Debt - current					(32,000)
Debt - non-current					$ (36,000)
Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment			3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment			5 years
Trade Accounts Receivable | Customer Concentration Risk
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage			47.00%		49.00%